It’s time for the annual Perseid meteor shower, one of the best of the year.
The Perseids are peaking this weekend and well into Monday morning. The best time to see the Perseids is after midnight and especially from 2 to to 5 a.m.
And this year there will be no moonlight interference. If you can get out into the countryside you may see 50 to 80 meteors or an hour. Maybe more than one every minute. In urban areas you can probably see five to 10 an hour.
They are called the Perseids because all of the meteors seem to emanate from the general direction of the constellation Perseus the Hero. Perseus rises high in the northeastern sky in the early morning hours.
Don’t restrict your meteor search to just that part of the sky. Lie back and roll your eyes all around the sky.
Most of the “shooting stars” are faint and rip across the sky rapidly, so the more eyes watching the big sky the better.
Meteors are often called shooting stars, but they’re actually just grains of dust and pebbles. The biggest ones may approach the size of small walnuts. This is all debris left behind by comets that have passed by the Earth and our sun.
Comets are basically dirty snow or ice balls that partially melt when they get close to the sun. Debris from these partially melted comets is left in their wake and gravity between the particles keeps the debris trail intact.
The debris trail that causes the Perseids is comet Swift-Tuttle that comes by this part of our solar system about every 130 years and last traveled by in 1992. Because of that recent visit the Perseid meteor shower was even more prolific in much of the 1990s, but even now it’s still a great show.
There were some who thought that Swift-Tuttle could possibly collide with the Earth in 2126, but that’s been played down by a lot of astronomers, but stay tuned.
In the meantime, tiny pieces of Comet Swift-Tuttle will slam into our atmosphere at speeds more than 40 miles a second, and be easily incinerated before they can get anywhere near us. Most bits of this debris burn up around 40 miles high.
So where does the light come from? The answer is the process of ionization. These debris particles are zipping through our atmosphere so fast that the column of air they’re going though is being destabilized. Zillions of electrons from atoms that make up Earth’s atmosphere get temporally bounced away from the nucleus of zillions and zillion of atoms. As these electrons bounce away and then bounce back they produce energy in the form of bright light.
In fact, a lot of meteors you see leave a trail that can take a few seconds to fade. What you’re seeing is the column of air that the meteor ripped through stabilizing and getting its act back together.
I strongly advise that you get your act together and catch the Perseids. It’s one of Mother Nature’s best shows of the year.
Celestial hugging this week: On Monday night the crescent moon will be parked just below the bright planet Saturn. It will be great to gaze at with just your eyes, but if you point even a small telescope at both the moon and Saturn it will make it that much better.
It may be a little fuzzy, but you should be able to make out Saturn’s ring system with your scope.
Mike Lynch’s website: www.lynchandthestars.com.
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